An animal model of alcohol addiction is being developed. A gastric cannula is implanted in rats together with a thermistor. The rats are then injected with ethanol automatically, the pump cutting out when their body temperature drops below a certain point. After continuous exposure to intragastric alcohol for 3 days, the rats are given free choice between 10% alcohol and water. The yield of rats choosing large quantities of ethanol is 50-60%. We are investigating the reasons for failure in those rats where "addiction" fails to develop. We are showing that tolerance develops in all animals and it seems that conditioned aversion is responsible for at least some of the failures. The experiment is being redesigned to minimize conditioned aversion to alcohol.